Dancer Posted March 24 Share Posted March 24 6 hours ago, Funky said: Are you sure about that? I could imagine them being in the way, if you wanted to accelerate or brake very hard.. But balancing left/right - they are not in the way at all. Front/Back of euc having extra small wheel. If those wheels would be under pedals - then yeah, they are in the way. Try to ride a bicycle with a fixed front wheel. Quote Link to comment Share on other sites More sharing options...
Funky Posted March 24 Share Posted March 24 (edited) 1 hour ago, Dancer said: Try to ride a bicycle with a fixed front wheel. He never said that those wheels would touch the ground... At least while being powered on. Otherwise one could not ride at all. At least i imagined those wheel not touching the ground while you are riding. But if something goes wrong and EUC stops working mid ride - you would land on back or front wheel. Letting one simply ride out till stop.. Edited March 24 by Funky Quote Link to comment Share on other sites More sharing options...
alcatraz Posted March 25 Share Posted March 25 Yeah they don't touch. One situation when they wouldn't work is going up/down inclines. They'd touch then. Quote Link to comment Share on other sites More sharing options...
alcatraz Posted March 25 Share Posted March 25 You'd also need a way to produce a braking force. Short the motor wires? That's a scary mechanism. Maybe have friction bearings in the dummy wheels? Quote Link to comment Share on other sites More sharing options...
Dancer Posted March 25 Share Posted March 25 15 hours ago, Funky said: He never said that those wheels would touch the ground... At least while being powered on. Otherwise one could not ride at all. At least i imagined those wheel not touching the ground while you are riding. But if something goes wrong and EUC stops working mid ride - you would land on back or front wheel. Letting one simply ride out till stop.. "ride out till stop" won't work. You can't balance left to right. Quote Link to comment Share on other sites More sharing options...
Warxcell Posted March 25 Share Posted March 25 On 3/20/2024 at 8:17 PM, Chriull said: That's the firmwares motor current limitation so the mosfets won't fry (to often...) Seems you overpowered the mosfets... That's a senseless value reported from begode wheels since the beginning (don't know if they corrected it anytime?). Multiplying battery voltage with motor current gives nonsense... If such in such a construct mosfets fry by overload on one board the mosfets of the other board will be fried just an instant later... ... and the added complexity of synchronizing two boards, decoupling a faulty board, etc will lead to much more possible faults As I said - I have done a lot more intenstive accelerations - like ~5kW reported power. (Yeah power could be wrong, but its always wrong, so 5KW is almost twice the power of when MOSFETs burned). So NO - I didn't overpowered the MOSFETs. Quote Link to comment Share on other sites More sharing options...
Funky Posted March 25 Share Posted March 25 4 hours ago, Dancer said: "ride out till stop" won't work. You can't balance left to right. Lean left, lean right. Anyways 1 wheel front and 1 wheel back is dumb idea in general.. Why use 3 wheels, when you could use 2 wheels and be much safer than 1 wheel. Quote Link to comment Share on other sites More sharing options...
Chriull Posted March 26 Share Posted March 26 On 3/25/2024 at 1:47 PM, Warxcell said: As I said - I have done a lot more intenstive accelerations - like ~5kW reported power. (Yeah power could be wrong, but its always wrong, so 5KW is almost twice the power of when MOSFETs burned). So NO - I didn't overpowered the MOSFETs. As standstill motor current is limited to ~200A. Motor current is limited to this 200A (by this "magnetic skipping") and at higher speeds the maximum possible current decreases according to the max torque over speed limit. Mosfet burden is highest at low speeds (highest possible current and no air drag for cooling) As it seems from the notes from the pull test the nikola never gives up and delivers max phase current as long as requested and until the first mosfets die? Prior burdening can weaken mosfets. The reported kW are quite irrelevant. Could of course have been some rare firmware glitch, quality issues, etc... Quote Link to comment Share on other sites More sharing options...
InfiniteWheelie Posted April 1 Share Posted April 1 (edited) As stated already, the solution is redundancy… Battery packs are already physically split in two (left/right side), so no extra cost here. High power cells are preferred for this. Controllers are not very large, you could certainly fit dual controllers up top. It wouldn’t add that much cost. Hall sensors are only needed above walking speed (thanks to sensorless operation), so no need for redundancy here. That would be good enough to avoid 99% of all cutouts. In my mind there’s zero reason for manufactures not to implement it. If you want to go one step further, you could use a 6 phase motor (dual independent 3 phase windings). One set of wires entering each side of the axle. If one set of phases shorts/disconnects you’d still have power. Edited April 1 by InfiniteWheelie 1 Quote Link to comment Share on other sites More sharing options...
Funky Posted April 1 Share Posted April 1 (edited) 4 hours ago, InfiniteWheelie said: Battery packs are already physically split in two (left/right side), so no extra cost here. High power cells are preferred for this. Doesn't always mean they are split at controller.. They can act as one big battery going in said controller. Meaning if one stops working - they all stop working. Edited April 1 by Funky Quote Link to comment Share on other sites More sharing options...
InfiniteWheelie Posted April 1 Share Posted April 1 (edited) @Funky I’m just talking about the physical battery cases being separate. It’s trivial to connect them differently at little to no cost. Edited April 2 by InfiniteWheelie 1 1 Quote Link to comment Share on other sites More sharing options...
rcgldr Posted April 2 Share Posted April 2 (edited) On 3/21/2024 at 10:27 PM, alcatraz said: How about having a dummy wheel in front and back to balance on until the wheel comes to a stop? In case this was missed, the result would be a bicycle with a locked front wheel. The normal method to turn on an EUC is to tilt it, which causes it to twist and steer due to camber effect or to twist the EUC directly. If there is a second wheel, that would prevent the main wheel from twisting. Edited April 2 by rcgldr Quote Link to comment Share on other sites More sharing options...
DavidB Posted April 2 Share Posted April 2 On 6/22/2019 at 6:28 AM, Wonderwebb said: I'm new to euc and am surprised no one has come up with something yet . I keep thinking of a magnetic catch that would hold two small casters one front one back that would deploy under power loss much like a fire door magnetic release. Can you point me to the old thread so I can see what you came up with ? I was thinking of this when I came across your post. But just a front wheel(s). (Skate truck) But maybe a UHMWPE slider would be better.Judging by the comments I don't think the others get this. It is only deployed when the motor cuts out. Would have to be almost instant. Quote Link to comment Share on other sites More sharing options...
TimDelaware Posted April 2 Share Posted April 2 On 4/1/2024 at 6:15 AM, InfiniteWheelie said: As stated already, the solution is redundancy… Battery packs are already physically split in two (left/right side), so no extra cost here. High power cells are preferred for this. Controllers are not very large, you could certainly fit dual controllers up top. It wouldn’t add that much cost. Hall sensors are only needed above walking speed (thanks to sensorless operation), so no need for redundancy here. That would be good enough to avoid 99% of all cutouts. In my mind there’s zero reason for manufactures not to implement it. If you want to go one step further, you could use a 6 phase motor (dual independent 3 phase windings). One set of wires entering each side of the axle. If one set of phases shorts/disconnects you’d still have power. Completely agree. I’d say anything more than electrical redundancy is fantasy land 1 Quote Link to comment Share on other sites More sharing options...
MetricUSA Posted Monday at 01:41 AM Share Posted Monday at 01:41 AM Sure it has been addressed but you people refuse to accept it... The wheel is capable of faster speeds of 100 km/m, but you're not supposed to ride faster than 40 km/h!!! Sads to say you idiots keep going trying to push it beyond its speed!!! Go figure... Quote Link to comment Share on other sites More sharing options...
TimDelaware Posted Monday at 06:10 AM Share Posted Monday at 06:10 AM 4 hours ago, MetricUSA said: Sure it has been addressed but you people refuse to accept it... The wheel is capable of faster speeds of 100 km/m, but you're not supposed to ride faster than 40 km/h!!! Sads to say you idiots keep going trying to push it beyond its speed!!! Go figure... Pushing beyond a wheels capability is stupid but equally doesn’t have anything to do with redundancy or failsafes 🤷♂️. We’re not trying to solve stupidity here Quote Link to comment Share on other sites More sharing options...
Dancer Posted Monday at 11:58 AM Share Posted Monday at 11:58 AM On 4/2/2024 at 3:41 AM, DavidB said: I was thinking of this when I came across your post. But just a front wheel(s). (Skate truck) But maybe a UHMWPE slider would be better.Judging by the comments I don't think the others get this. It is only deployed when the motor cuts out. Would have to be almost instant. Yes, I get that. But as soon as the second wheel touches the ground, you won't be able to balance sideways and you will fall before you can come to a stop. Quote Link to comment Share on other sites More sharing options...
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